The Evolving Maturity in
Ransomware Operations
A Black Hat Europe 2020 Whitepaper
December 2020
Mitchell Clarke and Tom Hall

ABSTRACT
Ransom demands are becoming larger, attackers smarter, and intrusions longer. Ransomware threat actors
are hitting European and global companies hard with more effective ransomware deployment resulting indevastating impacts to victim organisations. When they strike, their ransomware deployments are more
complete, more effective, and they are crippling many organisations to the point where there is often no clear
path back to business.
This whitepaper outlines different operating models in use by ransomware threat groups during 2020,
specifically ransomware as a service and partnership models. Ransomware as a service involves multiple
threat actors that make use of a central shared platform to automate and streamline repetitive processes
encountered during ransomware operations.
Partnership models involve handover between threat actors, often separating initial intrusion and privilege
escalation from mass deployment of ransomware extortion of victims. This allows threat actors to specialise in
specific stages of an intrusion lifecycle, enabling them to operate with increased efficiency and effectiveness.
This whitepaper reviews tradecraft that ransomware threat actors have employed across Europe in 2020. This
includes how ransomware crews leverage high-profile critical vulnerabilities to gain footholds in multiple
victims’ networks and return weeks or even months later to leverage those footholds into full-scaleransomware deployments.

INTRODUCTION
The ransomware industry has continued to evolve during 2020. Ransomware threat actors are increasingly
conducting full-scale network intrusions similar to those seen in nation-state Advance Persistence Threat(APT) or financially motivated criminal intrusions. Full-scale network intrusions allow threat actors to deploy
ransomware across the entirety of victim organisations, often with devastating consequences.
Historically, ransomware has often been deployed opportunistically or in a non-targeted manner where ahandful of systems or small network segments were infected. Several global high-profile, high-impact
ransomware infections in the past, such as WannaCry or NotPetya, were non-targeted events and were selfsustaining with no interaction with attackers after initial malware deployment.
Since the days of WannaCry and NotPetya, the ransomware industry has evolved as threat actors chaseever-increasing ransom pay-outs. Threat actors have matured from opportunistic ransomware deployment tobecome co-ordinated professional organisations with a focus on sustained traditional network intrusions inorder to be best placed to deploy ransomware as widely as possible across victim environments. Thisapproach to sustained intrusion and comprehensive ransomware deployment can take days, weeks, ormonths.
By deploying ransomware to the entirety of a victim network, threat actors are applying maximum pressure on
victim organisations to pay the demands set by the attackers. Mass ransomware deployments responded toby Mandiant are increasingly threatening business continuity and leaving victims with a decision between
paying ransoms and being unable to continue to trade or operate.
Additionally, ransomware threat actors are also increasingly stealing victim data and threatening to publicly
release stolen data thereby adding extra pressure to victim organisations.
With this continued evolution, ransomware attackers have become more effective and increasingly efficient.
Mandiant sees this play out in two different ransomware models:
1. Ransomware as a Service – which features automation and scale. This paper profiles REvil, a threat
group made up of individual affiliates using a common ransomware platform.
2. Partnership Models – where threat actors focus on different parts of an intrusion, such as traditional
network compromise, while others focus on ransomware deployment, data theft and extortion. This
paper profiles QAKBOT and DOPPELPAYMER groups, who perform different stages of the intrusion
and handoff victims between them.

2

REVIL AND SODINOKIBI
Overview
REvil refers to a collection of threat actors who use a common ransomware as a service platform created by athreat actor that goes by the name of UNKN or Unknown. UNKN began advertising for affiliates to join theplatform in mid-2019 and since then, many threat actors have joined REvil, gaining access to the automationand process benefits that the platform provides.
UNKN advertises that affiliates can retain 60 to 70 percent of ransoms in exchange for use of the platform.
Affiliates that perform well and obtain large and/or regular ransom payments will receive higher pay-outs whilepoorly performing affiliates will receive less and can potentially be removed from the platform.
This type of ransomware operation is known as an affiliate model. While each threat actor within the program
gains access to the SODINOKIBI ransomware used by the group, each affiliate operates independently.
This leads to REvil intrusions and SODINOKIBI ransomware deployments to vary widely in terms of tradecraft
and targeting as each threat actor operates in isolation.
REvil tradecraft described in this whitepaper is an amalgamation of multiple individual affiliates.

Ransomware as a Service Model
Ransomware as a service involves use of a central platform which automates and streamlines businessprocesses that are common to most ransomware intrusions. Threat actors have created these platforms to
reduce operator-effort required for repetitive and common tasks to increase both scale and pace of operations
while also improving the effectiveness of processes.
REvil's ransomware as a service platform provides affiliate threat actors with the following services:•

Malware provision and generation, enabling threat actors to generate new and unique malware
samples per victim or operation•

Ransom demands, enabling threat actors to centrally set and manage a ransom amount for thetargeted victim organisation•

Payment information, removing the burden of communicating and managing cryptocurrency walletdetails for each ransom operation•

Victim communications, allowing the attacker to negotiate the ransom amount and to share stolen
files to prove to victims that threat actors have successfully exfiltrated data from victim networks•

Cryptocurrency laundering, which reduces the attribution of cryptocurrency profits paid to affiliate
threat actors

The REvil ransomware platform provides automation, efficiency, and increased effectiveness during
ransomware operations.
Development of ransomware as a service platforms can be compared to the scale-out and scale-up of
legitimate businesses facing rapid growth opportunities.

Tradecraft
Whether an intrusion is performed by a nation-state sponsored APT group, a criminal group, or a ransomware
group, threat actors must step through common phases of an intrusion lifecycle, shown in Figure 1, to be able
to achieve their objectives.

3

Figure 1: An example targeted attack lifecycle for a full-scale network intrusion

REvil tradecraft varies between individual threat actors. Broadly, however, REvil threat actors have performed
APT-like intrusions during 2020 which are full-scale network intrusions that can span days, weeks, or evenmonths. REvil threat actors are employing tradecraft similar to that of APT or financial crime groups to gain
the highest level of privilege within victim organisations. This privilege, combined with effective organisationwide network reconnaissance and lateral movement, allows REvil attacker to launch devastating SODINOKIBI
ransomware deployments often impacting the entirety of a victim network.
These prolonged intrusions with APT-like tradecraft can have devastating consequences for victim
organisations when ransomware is deployed, often leaving them without the ability to perform basic day-today business operations.

Initial Compromise
REvil threat actors are leveraging high-profile and high-impact vulnerabilities of internet-facing edge devices
to mass-exploit many victims simultaneously.
Vulnerabilities in edge-devices are attractive for REvil threat actors as they are exposed to the internet by
design and provide a method of initial access to the victim corporate networks.
By conducting mass-exploitation of vulnerable edge devices, REvil attackers are able to gain access tomultiple victim organisations. REvil threat actors then likely triage these accesses to prioritise organisations
the actors believe will be more likely to pay ransoms.
During 2019, many vulnerabilities were discovered in internet-facing edge devices. REvil exploitation of thesewell-known vulnerabilities often occurred months after vulnerability disclosure and patch release.
Vulnerabilities exploited in edge-devices by the REvil threat actors include:•

VPN devices•

Web services•

Remote desktop appliances•Internet-facing remote desktop services

Establish Foothold
Due to the high number of vulnerable devices exposed to the internet, REvil threat actors who conduct massexploitation will often have a backlog of victims to triage and prioritise. Some of these threat actors will
progress intrusions from initial access to a surer setting by establishing additional remote access mechanisms
to victim environments. These methods may include:•

Use of Cobalt Strike BEACON malware

4•

VPN abuse•Installation of web shells on internet-facing victim web servers

Escalate Privileges
After establishing a foothold to victim organisations, REvil threat actors will use a multitude of privilege
escalation techniques in order to gain administrative access to victim environments that are similar to thoseused during APT, financial crime, or red team intrusions. These include but are not limited to:•Mimikatz and other password dumping utilities•

ProcDump to obtain process memory of the Windows Local Security and Authorisation Sub-system(LSASS)•

Passwords for privileged local administrator or domain accounts stored as cpassword objects within
legacy group policy preferences•

Credentials stored within domain shares, for example, hard-coded credentials within corporate
PowerShell scripts•

Credentials stored in user profiles, such as text files or Excel spreadsheets

Internal Reconnaissance
REvil threat actors are performing comprehensive internal network reconnaissance in an attempt to fully
understand victim networks and maximise the effectiveness of ransomware deployments. REvil threat actors
are using network scanning and domain enumeration tools to discover:•

Additional corporate networks•

Additional Active Directory domains

Tools employed by REvil attackers include:•

Advanced IP Scanner•

SoftPerfect Network Scanner•

Bloodhound, an open-source domain enumeration tool•

Built-in Windows commands to gather Active Directory information

Move Laterally
Once REvil threat actors discover and gain familiarity with victim networks, they will move laterally to network
segments and systems of interest using stolen administrative credentials and using multiple tools andtechniques, such as:•

WMIExec (remote execution tool)•

SMBExec (remote execution tool)•

CrackMapExec (remote execution tool)•

PsExec (remote execution tool)•

RDP (legitimate Microsoft remote desktop service)5

Maintain Presence
In order to retain access to additional network segments or environments within victim organisations, REvil
threat actors will often establish additional persistent backdoors or abuse legitimate remote access solutionsin preparation for organisation wide SODINOKIBI ransomware deployment.
This provides the attackers with independent remote access to each targeted network segment.
Methods of persistence vary between individual REvil affiliates, however Mandiant has observed repeated useof the following persistence methods:•

Installation of commercial/freemium internet remote desktop software•

Cobalt Strike BEACON•

Web shells installed on internet-facing victim web servers•

Continued VPN abuse using compromised credentials•

Continued abuse of remote desktop appliances using compromised credentials

Data Theft
Prior to deploying SODINOKIBI ransomware, REvil threat actors will often steal data from victim
organisations.
Data theft is conducted prior to ransomware deployment to increase pressure on victim organisations to pay
ransom demands. The REvil threat actors will threaten to publicly release stolen data, extorting victims andincreasing pressure.
Methods of data theft used by REvil include:•

Compression and exfiltration of targeted data using malware deployed within victim organisations•

Installation of commercial cloud data synchronisation platform software to upload targeted data. Once
installed, the commercial synchronisation software will upload targeted data to the cloud platform. The
threat actors are then able to access victim data via the commercial cloud platform.

Ransomware Deployment
After gaining administrative access to domains and networks within victim organisations, the REvil attackers
will prepare and deploy SODINOKIBI ransomware as widely as possible.
Prior to deploying ransomware, REvil attackers have been observed attempting to increase the likelihood of
successful SODINOKIBI execution by disabling antivirus software across victim environments, usually byeither:•Accessing central corporate antivirus consoles using administrative credentials to disable antivirus
across the entire victim estate•

Mass-deploying open-source administrative scripts that disable antivirus to individual systems within
the victim estate.

After disabling antivirus software across victim environments, the most common method of SODINOKIBI
ransomware deployment is the abuse of corporate Group Policy and unrestricted file shares:
1. The attacker will create file shares on victim domain controllers accessible to all users and systems
within the targeted domain. The file shares are used to store SODINOKIBI ransomware binaries.
2. The attacker then creates a Group Policy Object in the default domain policy for all computers tocreate and execute a scheduled task. The scheduled task downloads and executes SODINOKIBI
ransomware binaries from the open file shares created on targeted domain controllers.

63. When the computers within the targeted domain next update Group Policy, they create and executethe attacker-created scheduled task which in turn downloads and executes the SODINOKIBI
ransomware.
After creating malicious group policy to deploy SODINOKIBI ransomware across a targeted domain, the REvil
attackers will often use remote execution tools to deploy the SODINOKIBI ransomware to systems that havenot updated Group Policy objects or have otherwise not been infected with ransomware. This action
maximises the number of victim computers ransomed by the attacker and increases the impact to victim
organisations.
Once executed, SODINOKIBI will encrypt files on infected computers and create ransom messages that guidevictims to the REvil ransomware as a service platform for ransom negotiation and payment.

QAKBOT AND DOPPELPAYMER
Partnership Model
During 2020, Mandiant responded to DOPPELPAYMER ransomware deployments across Europe andglobally where initial access was achieved through widespread use of QAKBOT malware.
In contrast to REvil’s affiliate model where individual threat actors are responsible for end-to-end intrusions
from initial access to ransomware deployment, QAKBOT and DOPPELPAYMER employ a partnership model
where one threat actor is responsible for initial access, privilege escalation, and lateral movement which isthen passed to another threat actor for DOPPELPAYMER ransomware deployment.

QAKBOT Modules
QAKBOT is often delivered to victims via unsophisticated, yet effective, spear phishing campaigns. QAKBOT
is a modular backdoor originally used as a banking trojan and has since been leveraged as a precursor to
DOPPELPAYMER ransomware deployment.
QAKBOT is a modular backdoor that allows for individual capabilities to be deployed to infected systems. Key
modules include:•

Email Staging Module: A standalone module independent from other QAKBOT modules that steals
email from a local Outlook instance using MAPI connections. Email data is compressed, base 64
encoded, and sent to a hardcoded command and control server.

•

Cobalt Strike Module: Loaded using one of two methods:•oBy executing a file dropped using the malwareo

Via a pre-configured DLL as a QAKBOT module

Web Inject Module: Traditional banking trojan functionality that targets JavaScript loaded in Northern
American banking organisation websites.

After infecting organisations with QAKBOT malware and gaining privilege within targeted environments, threat
actors will hand access to QAKBOT backdoors to other threat actors using DOPPELPAYMER to mass-deploy
ransomware across victim networks.

DOPPELPAYMER Deployment and Execution
After obtaining access to victim networks using existing QAKBOT infections, threat actors will deploy
DOPPELPAYMER ransomware using techniques similar to other ransomware operators:•

PsExec7

•Background Intelligent Transfer Service (BITS) Jobs•

Scheduled Tasks

Once executed, DOPPELPAYMER ransomware performs the following actions:••

Enumerate all local users of a system and change the password for each user. This prevents victims
from logging into infected systems. The password is generated by combining a pre-configured stringwith an MD5 hash of the system name, for example:oPreconfigured string: TtXtE9n3oComputer name hash: 384DFCCEE8DB9F89ED2859E3F32F6AF5

oFull password: TtXtE9n3&384DFCCEE8DB9F89ED2859E3F32F6AF5

The ransomware will then copy legitimate services and replace them with a copy of itself in order toestablish persistence:oooFile: <random>.exe§

Path: %APPDATA%\<random>.exe§

Note: Copy of DOPPELPAYMER binary

Service: <random_service>§

Path: %WINDIR%\system32\<random_service>.exe§

Note: Ransomware Service

Service: <random_service>-1§

Path: %WINDIR%\system32\<random_service>.exe-1§

Note: Backup of Service•

The ransomware will then modify the boot configuration database of the infected system in order todisable start up repair and to execute the ransomware during safe boot.

•The ransomware will also modify group policy to display a ransom message prior to logon which
directs victims to the threat actor’s TOR website for ransom negotiation and payment.

•

Finally, after rebooting the system, the DOPPELPAYMER ransomware will begin encrypting files on
the affected system and will create ransom notes to direct victims to the threat actor’s TOR website.

CONCLUSION AND OUTLOOKWith increased impact and visibility, the threat of ransomware has widely become a boardroom issue, now
placing highly on corporate risk registers. Enterprise-wide ransomware infections are becoming businesshalting events, with many organisations facing loss of revenue and critical impact to business continuity.
Ransomware continues to be a growing problem beyond 2020, both in Europe and globally. During 2020, thefollowing key metrics for ransomware intrusions have increased:•

Ransom amounts•

Number of victim organisations•

Damage incurred by increasingly effective organisation-wide ransomware deployments•

Extortion for stolen data

With ransom profits assumedly being at an all-time high, ransomware threat actors have continued incentive
to automate operations, gain additional operators, partners, and/or affiliates, as well as to scale platforms toallow attackers to infect more organisations with increasing efficiency and devastation.
Increased impact to business continuity may increase or better focus information security spending andencourage organisations to secure environments and improve security baselines. While this may protectorganisations from tradecraft currently employed by ransomware threat actors, it is likely that attackers will
improve tradecraft in a continuous manner as seen in APT and financial crime threat actors.

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While ransomware intrusions have been highly effective during 2020, organisations can protect themselves
and prevent these intrusions by focusing information security budgets on improving security programs andbaselines including:•Vulnerability management programs, ensuring critical vulnerabilities for internet facing infrastructure
as well as critical internal privilege escalation vulnerabilities are patched as soon as possible•

Ensuring networks are actively and effectively monitored at scale for intrusions•

Implementing robust privilege access management solutions•

Ensuring critical or sensitive data is access controlled and cannot be easily exfiltrated•

Ensuring that robust backup solutions are in place and regularly tested to ensure that organisations
are able to rapidly recover during a ransom event

9FireEye, Inc.

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